JavaScript正則表達式校驗非零的負整數實例

!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 html xmlns="http://www.w3.org/1999/xhtml">
 head>
  title>/title>
  script type="text/javascript">
   function validation() {
    var val = document.getElementById("txtNumber").value;
    var regu = /^-[1-9]\d*$/;
    if (val != "") {
     if (!regu.test(val)) {
      document.getElementById("labResult").style.color = "red";
      document.getElementById("labResult").innerHTML = "驗證失??！";
     } else {
      document.getElementById("labResult").style.color = "green";
      document.getElementById("labResult").innerHTML = "驗證成功！";
     }
    }
   }
  /script>
 /head>
 body>
  input id="txtNumber" name="txtNumber" type="text" />
  input id="btnValidation" name="btnValidation" type="button" value="校驗" onclick="validation()" />
  驗證結果：label id="labResult" >/label>
 /body>
 /html>